Scroll compressor with supporting member in axial direction

ABSTRACT

A scroll compressor includes a case, a fixed scroll having a fixed wrap, and an orbiting scroll having an orbiting wrap coupled to the fixed wrap to define compression chambers. A driving motor has a crankshaft, the crankshaft having one end portion coupled to the orbiting scroll, a main frame and an auxiliary frame fixed onto an inner wall of the case to support the crankshaft, respectively, and a thrust plate having an annular shape and interposed between the auxiliary frame and the crankshaft to support the crankshaft in an axial direction, wherein a plurality of oil channels are formed on a surface of the thrust plate so as to communicate an inside and an outside of the thrust plate with each other.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. §119 to KoreanApplication No. 10-2011-0101494 filed in Korea on Oct. 5, 2011, which ishereby incorporated by reference for all purposes as if fully set forthherein

TECHNICAL FIELD

The present disclosure relates to a scroll compressor having asupporting member in an axial direction, and more particularly, a scrollcompressor having a member for axially supporting a crankshaft to whicha rotor of the scroll compressor is fixed.

BACKGROUND ART

In general, a scroll compressor is a compressor for compressingrefrigerant gas by varying volumes of compression chambers formed by apair of scrolls which face each other. The scroll compressor is beingwidely used, especially, in an air conditioner, in the aspects of highercompression efficiency, lower vibration and noise, a more reduced sizeand a lighter weight, as compared to a reciprocal compressor or a rotarycompressor.

FIG. 1 is a sectional view schematically showing one exemplaryembodiment of a scroll compressor. As shown in FIG. 1, the scrollcompressor includes a case 1 having an inner space which is divided intoa suction space 11 as a low pressure part and a discharge space 12 as ahigh pressure part, a driving motor 2 installed in the suction space 11of the case 1 to generate a rotational force, and a main frame 3 fixedbetween the suction space 11 and the discharge space 12 of the case 1. Afixed scroll 4 is fixed onto an upper surface of the main frame 3. Anorbiting scroll 5, which forms two pairs of consecutively movingcompression chambers P together with the fixed scroll 4, is installed toorbit between the main frame 3 and the fixed scroll 4 by beingeccentrically coupled to a crankshaft of the driving motor 2. An Oldhamring 6 for preventing self-rotation of the orbiting scroll 5 isinstalled between the fixed scroll 4 and the orbiting scroll 5.

A suction pipe 13 is coupled to communicate with the suction space 13 ofthe case 1, and a discharge pipe 14 is coupled to communicate with thedischarge space 12.

The driving motor 2 includes a stator 21 fixed onto an inner surface ofthe case 1, and a rotor 22 located inside the stator 21 and coupled tothe crankshaft 23. In addition, a lower end portion of the crankshaft 23is supported by an auxiliary frame 7.

In the scroll compressor having the structure, the crankshaft 23 issupported in a radial direction by the main frame 3 and the auxiliaryframe 7 which are located at both sides of the crankshaft 23 based onthe rotor 22, and supported by the auxiliary frame 7 in an axialdirection. In general, to the crankshaft of the scroll compressor isapplied a rotational force in response to rotation of the driving motorand a compression force of gas, which is repulsive to the rotationalforce. Namely, forces in a radial direction are generally applied to thecrankshaft. Accordingly, journal bearings may be provided at the mainframe and the auxiliary frame to support the crankshaft for smoothoperation.

However, in recent time, a type of scroll compressor which controls arotating speed of the driving motor is widely used. This invertercontrol type scroll compressor exhibits a high rotating speed variationwidth of the crankshaft and sets a top speed to be higher than that ofthe related art scroll compressor. This structure further requires anelement for supporting the crankshaft more stably in the axialdirection.

DISCLOSURE OF THE INVENTION

Therefore, to obviate those problems, an aspect of the detaileddescription is to provide a scroll compressor having a supporting membercapable of stably supporting a crankshaft in an axial direction.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein,there is provided a scroll compressor including a case, a fixed scrollhaving a fixed wrap, an orbiting scroll having an orbiting wrap coupledto the fixed wrap to define compression chambers, the orbiting scrollperforming an orbiting motion with respect to the fixed scroll, adriving motor having a crankshaft, the crankshaft having one end portioncoupled to the orbiting scroll, a main frame and an auxiliary framefixed onto an inner wall of the case to support the crankshaft,respectively, and a thrust plate having an annular shape and interposedbetween the auxiliary frame and the crankshaft to support the crankshaftin an axial direction, wherein a plurality of oil channels may be formedon a surface of the thrust plate so as to communicate an inside and anoutside of the thrust plate with each other.

In the aspect of the present disclosure, the scroll compressor mayfurther include the thrust plate for supporting the crankshaft in theaxial direction, which may result not only in supporting of thecrankshaft in the axial direction but also in reduction of a frictionalforce generated due to an axial rotation of the crankshaft. Especially,the oil passages may be formed on the surface of the thrust plate toallow oil to be smoothly supplied onto a frictional surface between thecrankshaft and the thrust plate, thereby improving lubricationperformance. Here, the oil passages may connect an outer circumferentialsurface and an inner circumferential surface of the thrust plate,namely, communicate inside and outside of the thrust plate with eachother, so that oil existing at the outer circumferential surface of thethrust plate can smoothly circulate through the oil passages. This mayresult in reduction of damage due to an introduction of foreignmaterials and simplification of a fabricating process.

Here, the plurality of oil channels may have a linear shape or acylindrical shape.

Each of the plurality of oil channels may extend to be inclined withrespect to a radial direction of the annular thrust plate, to allow oilexisting at the outer circumferential surface of the thrust plate to besmoothly introduced.

The oil channels may be formed to allow oil existing outside the thrustplate to be introduced to an inside of the thrust plate in response torotation of the crankshaft. As one example, if it is assumed that an endof each oil passage located outside the thrust plate is an inlet portand another end thereof located inside the thrust plate is an outletport, the outlet port may located by being spaced apart from the inletport by a predetermined angle on a circumference with respect to arotating direction of the crankshaft. Accordingly, the oil can beintroduced along the rotating direction of the crankshaft and smoothlyflow along the oil passages due to a frictional force against thecrankshaft, thereby facilitating the oil circulation.

In the meantime, for more smooth oil supply, the thrust plate may belocated lower than an appropriate minimum oil level.

A protrusion which is inserted into a stopping groove formed at theauxiliary frame may be formed at an outer circumferential portion of thethrust plate. This may prevent the thrust plate from rotating togetherwith the crankshaft, resulting in prevention of lowering of lubricationperformance.

In accordance with another exemplary embodiment of the presentdisclosure, there is provided a scroll compressor including a case,first and second supporting units fixed to the case, a crankshaftrotatably supported by the first and second supporting units, thecrankshaft having a facing surface facing the second supporting unit inan axial direction, a driving motor to rotate the crankshaft, acompression unit coupled to the crankshaft to compress fluid, and athrust bearing member located between the facing surfaces of thecrankshaft and the second supporting unit, wherein the thrust bearingmember may include an oil introduction element disposed to be sunk inlubricating oil and configured to allow the lubricating oil to beintroduced between frictional surfaces in response to rotation of thecrankshaft.

In accordance with the aspects of the present disclosure, a thrust platefor supporting a crankshaft in an axial direction may further beprovided so as to support the crankshaft in the axial direction and alsoreduce a frictional force generated due to an axial rotation.Especially, oil passages may be formed on a surface of the thrust plateso as to allow oil to be smoothly supplied onto a frictional surfacebetween the crankshaft and the thrust plate, resulting in improving of alubrication performance. Here, the oil passages may connect an outercircumferential surface and an inner circumferential surface of thethrust plate, namely, communicate inside and outside of the thrust platewith each other, so that oil existing at the outer circumferentialsurface of the thrust plate can smoothly circulate through the oilpassages. This may result in reduction of damage due to an introductionof foreign materials and simplification of a fabricating process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an inner structure of a generalscroll compressor according to the related art;

FIG. 2 is a sectional view showing an inner structure of a scrollcompressor in accordance with one exemplary embodiment of the presentdisclosure;

FIG. 3 is an enlarged sectional view showing a lower part of the scrollcompressor shown in FIG. 2;

FIG. 4 is a partially cut perspective view showing a portion where athrust plate is mounted in the scroll compressor shown in FIG. 2;

FIG. 5 is a planar view of the thrust plate shown in FIG. 2;

FIG. 6 is a planar view showing another exemplary embodiment of a thrustplate; and

FIG. 7 is a graph showing a variation of an input reduction according toa type of thrust plate.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below in detailwith reference to the accompanying drawings where those components arerendered the same reference number that are the same or are incorrespondence, regardless of the figure number, and redundantexplanations are omitted. In describing the present invention, if adetailed explanation for a related known function or construction isconsidered to unnecessarily divert the gist of the present invention,such explanation has been omitted but would be understood by thoseskilled in the art. The accompanying drawings are used to help easilyunderstood the technical idea of the present invention and it should beunderstood that the idea of the present invention is not limited by theaccompanying drawings. The idea of the present invention should beconstrued to extend to any alterations, equivalents and substitutesbesides the accompanying drawings.

Hereinafter, description will be given in detail of the exemplaryembodiments of a scroll compressor having a supporting member in anaxial direction, with reference to the accompanying drawings.

FIG. 2 is a sectional view showing an inner structure of a scrollcompressor in accordance with one exemplary embodiment of the presentdisclosure, and FIG. 3 is an enlarged sectional view showing a lowerpart of the scroll compressor shown in FIG. 2. As shown in FIGS. 2 and3, a scroll compressor 100 according to the one exemplary embodiment mayinclude a case 110 having a hermetic inner space, a compression unit 121installed within the case 110 to compress a refrigerant, and a drivingmotor 141 installed within the case 110 to provide a driving force tothe compression unit 121.

At one side of the case 110 may be provided a suction pipe 111 and adischarge pipe 113 for allowing introduction and discharge of arefrigerant, respectively. The compression unit 121 may be installed atan upper part within the case 110. The compression unit 121 may includea fixed scroll 123 having an involute wrap 125 and fixed into the case110, and an orbiting scroll 133 coupled to orbit with respect to thefixed scroll 123 and having an involute wrap 135.

The driving motor 141 may include a stator 143 fixed into the case 110,and a rotor installed within the stator 143 to be rotatable based on thecrankshaft 147. An eccentric portion 148 for driving the orbiting scroll133 may be formed at an upper region of the crankshaft 147. A thrustsurface 149 for supporting the crankshaft 147 in an axial direction maybe formed at a lower region of the crankshaft 147. A main frame 151 andan auxiliary frame 161 for rotatably supporting the crankshaft 147 maybe installed at the upper region and the lower region of the crankshaft147, respectively.

An upper bearing 153 for rotatably supporting an upper portion of thecrankshaft 147 in an accommodating manner may be formed at a centralregion of the main frame 151. The auxiliary frame 161 may have a shapeof a triangular case whose top is open. A coupling opening 163 in whicha lower bearing member 201 is accommodated may penetrate through acentral region of a lower portion of the auxiliary frame 161. A nut 164to which a fixing bolt 177 is coupled may be formed at a periphery ofthe coupling opening 163.

The lower bearing member 201 may include a flange portion 203 having atriangular shape to be received in the auxiliary frame 161, and acylindrical portion 213 formed at a lower side of the flange portion 203and having a cylindrical shape. A radial bearing portion 215 and athrust bearing portion 217 may be formed in the cylindrical portion 213so as to support the crankshaft 147 in a radial direction and an axialdirection, respectively. A bolt opening 205 may be formed at the flangeportion 203 to allow the flange portion 203 to be integrally coupled tothe auxiliary frame 161 by the fixing bolt 177.

In the meantime, a thrust plate 221 having an annular shape may becoupled between the crankshaft 147 and the thrust bearing portion 217.Accordingly, the thrust plate 221 may contact the crankshaft 147 toprevent abrasion of the thrust bearing portion 217. A protrusion 223 mayprotrude outwardly from one side of the thrust plate 221 in a radialdirection. A stopping groove 218 in which the protrusion 223 is insertedmay be formed at the lower bearing member 201. The protrusion 223 may beinserted into the stopping groove 218 so as to prevent the thrust plate221 from rotating by itself in response to rotation of the crankshaft147.

The thrust plate 221 may be located lower than an appropriate minimumoil level represented by h_(min) in FIG. 3. This may allow the thrustplate 221 to always be sunk in oil, resulting in further improvement oflubrication performance.

As shown in FIG. 5, the thrust plate 221 may include a plate main body222 having an annular shape, and the protrusion 223 protruding from oneside of the plate main body 222. A plurality of oil channels 224 may beformed at the surface of the plate main body 222. FIG. 5 exemplarilyshows totally 8 oil channels 224, but the total number may be randomlyset according to a diameter or the like of the plate. The oil channels224 may have a linear shape and be inclined with respect to a radialdirection of the plate main body 222.

Here, an inclined direction of the oil channels 224 may be decided suchthat an oil inlet port 224 a is located more behind an oil outlet port224 b on a circumference, with respect to a rotating direction of thecrankshaft 147 indicated by an arrow. Accordingly, oil existing at anouter circumferential portion of the plate main body 222 can be smoothlyintroduced into an inner circumferential portion of the plate main body222. The oil channel 224 may extend to cross an outer circumferentialsurface and an inner circumferential surface of the plate main body 222,and for the sake of explanation, it is referred to as an open typechannel.

The presence of the oil channels may allow oil to be smoothly introducedbetween the thrust surface 149 and the plate main body 222 so as to beevenly provided onto a contact surface. Also, pressure generated by theintroduced oil can be applied to the thrust surface 149 to push thecrankshaft 147 up. This may result in further reduction of a frictionalforce.

Without limit to the structure of the oil channel, an oil channel, asshown in FIG. 6, may be formed to be close to an inner circumferentialsurface of a plate main body without contacting each other. This isreferred to as a closed type channel. Upon employing this closed typechannel, introduced oil cannot be discharged and accordingly strongeroil pressure than the open type channel can be applied. However, in theclosed type channel, when a chip generated due to friction or otherforeign materials are introduced, those things may not be dischargedimmediately, which may cause a contact surface to be damaged.

FIG. 7 is a graph showing a variation of an input reduction according toa type of oil channel. Types of oil channels represented by A to C areas follows.

Type Number Width (mm) Depth (mm) A Closed 12 1 0.1 B Closed 8 1.5 0.25C Open 8 1.5 0.25

As shown in FIG. 7, it can be understood that the open type C exhibitsthe highest input reduction at an entire range of a rotating speed.Especially, it can be noticed that as a width and a depth increase more,more oil flows and consequently the input reduction increases. It canalso be noticed through comparison of the oil channels B and C whichhave the same size and number, the open type C is more advantageous thanthe closed type B in view of the input reduction.

1. A scroll compressor comprising a case; a fixed scroll having a fixedwrap; an orbiting scroll having an orbiting wrap coupled to the fixedwrap to define compression chambers, the orbiting scroll performing anorbiting motion with respect to the fixed scroll; a driving motor havinga crankshaft, the crankshaft having one end portion coupled to theorbiting scroll; a main frame and an auxiliary frame fixed onto an innerwall of the case to support the crankshaft, respectively; and a thrustplate having an annular shape and interposed between the auxiliary frameand the crankshaft to support the crankshaft in an axial direction,wherein a plurality of oil channels are formed on a surface of thethrust plate so as to communicate an inside and an outside of the thrustplate with each other.
 2. The compressor of claim 1, wherein theplurality of oil channels have a linear shape.
 3. The compressor ofclaim 2, wherein each of the plurality of oil channels extends to beinclined with respect to a radial direction of the annular thrust plate.4. The compressor of claim 1, wherein the oil channels are formed toallow oil existing outside the thrust plate to be introduced to aninside of the thrust plate in response to rotation of the crankshaft. 5.The compressor of claim 4, wherein if it is assumed that an end of eachoil passage located outside the thrust plate is an inlet port andanother end thereof located inside the thrust plate is an outlet port,the outlet port is located by being spaced apart from the inlet port bya predetermined angle on a circumference with respect to a rotatingdirection of the crankshaft.
 6. The compressor of claim 1, wherein thethrust plate is located lower than an appropriate minimum oil level. 7.The compressor of claim 1, wherein a protrusion is formed at an outercircumferential portion of the thrust plate so as to be inserted into astopping groove formed at the auxiliary frame.
 8. A scroll compressorcomprising: a case; first and second supporting units fixed to the case;a crankshaft rotatably supported by the first and second supportingunits, the crankshaft having a facing surface facing the secondsupporting unit in an axial direction; a driving motor to rotate thecrankshaft; a compression unit coupled to the crankshaft to compressfluid; and a thrust bearing member located between the facing surfacesof the crankshaft and the second supporting unit, wherein the thrustbearing member comprises an oil introduction element disposed to be sunkin lubricating oil and configured to allow the lubricating oil to beintroduced between frictional surfaces in response to rotation of thecrankshaft.
 9. The compressor of claim 8, wherein the thrust bearingmember is fixed to the second supporting unit to be prevented from beingrotated.
 10. The compressor of claim 8, wherein the oil introductionelement comprises a plurality of oil channels formed on a surface of thethrust bearing member.
 11. The compressor of claim 10, wherein thethrust bearing member has an annular shape, and the oil channels extendto communicate inside and outside of the thrust bearing member with eachother.
 12. The compressor of claim 11, wherein the plurality of oilchannels have a linear shape.
 13. The compressor of claim 12, whereineach of the plurality of oil channels extends to be inclined withrespect to a radial direction of the thrust plate.
 14. The compressor ofclaim 11, wherein if it is assumed that an end of each oil passagelocated outside the thrust plate is an inlet port and another endthereof located inside the thrust plate is an outlet port, the outletport is located by being spaced apart from the inlet port by apredetermined angle on a circumference with respect to a rotatingdirection of the crankshaft.